In answering questions over the years I have found for questions relative to things that anti's put up I have learned for myself that they only care about tearing down faith and belief. Really - the most important thing is to do the basics (prayer, scripture study, attend church, service, etc.) and build one's faith on the immovable foundation of the true gospel of Jesus Christ. If you have prayed about the church and received your testimony - hold on fast to that and keep your faith. If Joseph Smith was a true prophet of God - then nothing else really matters. You are never going to be able to completely prove one side or the other. We live on this earth by faith. God wants us to believe and trust in Him. We need to have faith. 
 
Now - for helping with some of the knowledge and facts about the gospel. The scriptures and all the manuals the church has is a wealth of information and knowledge. There is so much there that is faith-promoting and upbuilding and good. I would stick with those things and ignore the false slings and arrows that come from the adversary from all directions and sides. 
 
Lastly - if you absolutely have to have proofs and rebuttals and all kinds of things to prove the church and gospel (which is not the way to go) - there is a website called http://www.fairlds.org/. Fairlds.org is put together by very smart, knowledgeable members of the church who are defenders of the faith. In their vernacular they are "apologists" - just like there are biblical scholars/apologists. They defend through the words they write. You will see almost everything that the antis have come up with over the last 200 years are defended and explained. Fairlds.org is not supported nor sanctioned by the church, but I have found it to be incredibly good. 
As you can imagine I see lots of anti questions/statements/accusations/etc. It's most of the same stuff over and over and over again. I was curious in the beginning - maybe similar to what you are seeing, but I have resolved for myself that the Gospel is True and that the antis only want to hurt and damage our faith. Jesus said - By their fruits ye shall know them. I would suggest taking that advice and see what fruits the church brings - and what fruits the antis bring. I feel in many ways sad that the antis are so angry, bitter, and are wasting their lives trying to tear down goodness and virtue. I hope you will see the same thing. 
 
I would encourage you to hold fast to that which is good and ask your friend to allow you to be happy. I hope you will take the path of reading and studying to strengthen your faith - rather than trying to prove every little jot and tittle. God loves us and wants to help us. But we need to have faith and believe in Him and His Gospel. 
 
ps I could spend some time to come up with all the quotes and references to resolve the differences between the versions, but I have already spent time in the past doing that kind of work and to be honest - it is not faithbuilding - and it is a waste of time when I could be instead strengthening my faith and being of service to those in need. 
 
My prayers are with you. 
 
Thanks

The best way to explain this is to point out that the various accounts come from various sources. Most of which are second hand (someone saying what Smith told them). The only official version is the one that the Church publishes since it is the only one that is definitely traced back to the Prophet.